Enzymatic synthesis of phenylpyruvic acid labeled with deuterium, tritium, and carbon‐14

Abstract

The synthesis of isotopomers of phenylpyruvic acid, PPA, selectively labeled with hydrogen isotopes in the 3‐position of the side‐chain is reported. Three deuterium or tritium labeled isotopomers of L‐phenylalanine, L‐Phe, i.e. [(3S)‐2H]‐L‐, [(3S)‐3H]‐L‐, and doubly labeled [(3S)‐2H/3H]‐L‐Phe were synthesized using the enzyme phenylalanine ammonia lyase (EC 4.3.1.5). In the second step these isotopomers of L‐Phe were converted into [(3S)‐2H], [(3S)‐3H]‐, and [(3S)‐2H/3H]‐isotopomers of PPA using the enzyme L‐phenylalanine dedydrogenase (EC 1.4.1.20). The isotopomer of PPA labeled with 14C in carboxylic group, [1‐14C]‐PPA, was obtained in a two‐step enzymatic reaction using [1‐14C]‐cinnamic acid as the starting substrate. Copyright © 2008 John Wiley & Sons, Ltd.

Enzymatic synthesis of halogen derivatives of L‐phenylalanine and phenylpyruvic acid stereoselectively labeled with hydrogen isotopes in the side chain

“…Isotopomers of halogenated derivatives of PPA labeled with hydrogen isotopes in the (3S) position of the side chain were synthesized according to the modified procedure described earlier. 21 The sample of previously synthesized appropriate halogenated L-Phe labeled with hydrogen isotopes in the (3S) position, 0.05 mmol NAD + , and 1.2 U PheDH were dissolved in 2 mL of 0.1 M glycine buffer (pH 10.4). The reaction mixture was incubated at RT for 2 h. The reaction progress was monitored spectrophotometrically and by TLC.…”

The chemo- enzymatic synthesis of labeled l-amino acids and some of their derivatives

“…39. Three isotopomers of l -Phe i.e., [( 3S )- 2 H]- ( 1b ), [( 3S )- 3 H]- l -Phe ( 1a ) [15] and [( 3S )- 2 H/ 3 H]- l -Phe ( 1c ) [144] were converted into corresponding isotopomers of PPA, i.e., [( 3S )- 2 H]- ( 3a ), [( 3S )- 3 H]- ( 3b ), and [( 3S )- 2 H/ 3 H]-PPA ( 3c ) by oxidative deamination, catalyzed by enzyme l -phenylalanine dehydrogenase (PheDH, EC 1.4.1.20) [144].

Fig.

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“…Isotopomer [1- 14 C]-PPA ( 3d ) was synthesized as above using [1- 14 C]- l -Phe ( 1   h ) as a substrate [144]. …”

Enhanced enzymatic activity of phenylalanine dehydrogenase caused by cyclodextrins

“…Since PheDH is used for the synthesis of both Phe [10] and PP [19] isotopomers, it seems worthwhile to examine both biotransformations in the presence of CDs in order to check the possibility of enhancement of both the enzyme activity and recognition properties.…”